Use of samarium Sm 153 lexidronam for the treatment of dogs with primary tumors of the skull: 20 cases (1986-2006).

OBJECTIVE

To evaluate samarium Sm 153 lexidronam ((153)Sm-EDTMP) as a treatment option for dogs with bony tumors of the skull.

DESIGN

Retrospective case series.

ANIMALS

Dogs with multilobular osteochondrosarcoma (MLO) or osteosarcoma (OSA) of the skull.

PROCEDURES

Veterinary Medical Teaching Hospital records from the Universities of Missouri and Florida from 1986 to 2006 were searched for dogs with primary skull tumors treated with (153)Sm-EDTMP.

RESULTS

25 dogs were initially evaluated, with 5 dogs subsequently excluded because of inadequate follow-up or unrelated death. Seven OSAs and 13 MLOs were diagnosed. Tumors involved the occipital and frontal bones (n = 10), zygomatic arch and maxilla region (6), palate (3), and mandible (1). No clinically important adverse effects related to (153)Sm-EDTMP treatment were documented. Of the 20 dogs evaluated 21 days after injection with (153)Sm-EDTMP, 4 had subjective improvement, 13 had progressive disease, and 3 had insufficient follow-up. On the basis of radiographic findings, metastasis was suspected in 1 dog; 16 dogs had no metastasis evident, and medical records were insufficient for 3 dogs. Survival time, defined as the (153)Sm-EDTMP injection date to the date of death, ranged from 3 to 1,314 days (median, 144 days).

CONCLUSIONS AND CLINICAL RELEVANCE

The subjective improvement in 4 patients and lack of clinical evidence of adverse effects suggested that (153)Sm-EDTMP injection may be an option for the treatment of dogs with MLO or OSA of the skull when other treatments have failed or surgery is not possible.